SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c048b8b20d24c89a37a71a36800c666cba186ce13577b8718fe3c3b030bf1ba3' 
  AND token = 'GYFg/1UBGQQTLL6cYcMPKpEbgvKMWQ+XPkMKd3Fa7FQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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