SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e440395e1ddcbbaf9e4a6dfb5c6a4558a86eddae886aa16305ad7ee490a569d' 
  AND token = 'Qrrymrn8Br3pNcN7Jrv5bAIKkYIxXNlJdUFNTslVYMA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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