SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f75a2db8f73520850b85eb89db2835a692495418c7e14cb199a74ec1ed57f85e' 
  AND token = 'xa1XDwCwYvrMJR1CZ5eyres3A72doQFgQDRhsgSeZBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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