SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5eea6e1a54cf222713479d60d30a54a6f41905334066e5904a292c9c6326c4fe' 
  AND token = 'S2OfCdjOsfBpbxVQJRKzP+dSU8y6xxcK57lXf/PWkwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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