SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8c8e82d3d41c77316bce2c5114074ea86a1781a9751ff12a64a72dd6d54e165' 
  AND token = 'yl+Gg5vh5whcD0Af44GQhPDNQqRzWW2z1DuyuSwKa/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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