SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf5fd58e78c0304b2403bb342d66fa9664208e57f4a50d9f75a0e96b854e16c8' 
  AND token = 'VmQNWfaOgL9RyRMKkuJHDDSOa2u2l6gF5GB0zigUm5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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