SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad869fcee7dc56e69eb9468eb25dce62e991b3bce8f2c812854d2b781aa1ac94' 
  AND token = '7BcY7zbwXwFJVo5WUY/5ZAMDYceBGE7oeLChvC+tFLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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