SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66622583f8b6b2274c9538845e1ac4fa2c197b91ca7098f74204062ae595a68a' 
  AND token = '5hrGv8Z/074ByCnYcCfBUZMKfno1xVqWtSlNg13jfB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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