SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a8dd04072cb08094cc41c62f224822765c9f1646f89c1215a470445700961ad' 
  AND token = 's2X/0E0FFoVYU//Rp+rcuA0oL4/YDHRIkz2QxNpnpR4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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