SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8859337b11fb1e6d8b226646932f322aa04d695ca12b4c9a490248a24c9015cb' 
  AND token = 'N6X7JWUaevmz/xLSuUupqm+PoaTUOPpV2bRFahjVJgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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