SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f2a84dffea2a7a52884786b518847676f1c7782d0ce75c2a2dbe3d539eaebfb' 
  AND token = 'RfIsiMtTyv3lXCF/zot+nPLw1NmbdX2jf2WhRsPAYCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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