SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43fa4b5bba482c99cf176ee89dbaebfc3f66694a188f056ecde6390a47813fe4' 
  AND token = 'HjJc8eok6/6Jyot2OTwCgxVmSGvak/xaTz/zkcONEmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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