SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0692c27c8b094295d3f6f281a4ab3011565f220c9ebb4daa2224d32d1793a4d5' 
  AND token = 'bTwwEQhBe2FNjQkOFRYhryzuyefmhFMUjM1Ehj7KNBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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