SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f79bc91618e78e814914a6794728553dcb9c1aec5b49bff6bddeca133bfe1253' 
  AND token = '+5zgmn5/54Y8Qcm3FVbQhqlpmVvHcE0vSc5URMHmruo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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