SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6788a753aaa1ddc88604df6b86cebfb04c8398d81944b5e838ef048c91146f6' 
  AND token = 'GPQSzqMn3lBGurmYEsBDiYQQ66mT4oIPaWJrsppjCIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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