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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc4743621dd0b3f3c91dbb6a9afa1db61d939f9ad99ff266e75b2b964fb54871' 
  AND token = 'RR4jvzo+WQ2iKgCj/UuwkarReb4vJNkXczzK2/07nAc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}