SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f47881c9673b15b1f6661dbd56f4b566f1eea51b7e803ef55fdaebf7026770d' 
  AND token = 'cCqRGsYuXUwPHr0X9kcnN+aDmC2kkpSjl/ByGfaWCbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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