SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30905c730f358663cf162525dfe39861739b28363cbe13e01c4d2697b825e3c6' 
  AND token = 'MlLpwUud7SDAl3k1tVgHg/XPFdOzfDHnylX4M64sKaU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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