SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea10916f3148aa126e4a30978bab609e332de5be9e01f1b914e3863772c511de' 
  AND token = 'pM9dlOukyMyalXGNue5jiflC5Q1qzgsZ4cRvuljr8FY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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