SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed2c9f9b5f54d2923322f013a6fc45ce5adb58cbe76e70fec1510deb18c1777d' 
  AND token = 'dgYZtYtJubaKa800pwDok9k19yWbFXqzyZjv9pcR5Ls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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