SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c733b101b91f06280bba96067fe8b9ca1b97238ed62f361d2697db7387c911e' 
  AND token = 'a2kMjjF14bRnHNTpzwOxvmdq0kfKWJiIKas6mP7SXPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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