SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6870bd3c2002769b03d4bffd6ad660b11ddf62b7179c4d54644ac629749c7f8b' 
  AND token = 'YHBULzuwQzp7cmWrGb5wVTUEdoF3FLutadwEoGCkZqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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