SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a033aedae42bcd826d86ba6645c7ea78856c1fac3ae40edf31afd96ac56d30f2' 
  AND token = 'rNSqTpD7ZEchQwIacK1UMbiugcfhd91GIsgrb/M3lJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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