SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7992cae2470c1f58e943b55957565a1a255df75a53ccf3cdc892ccd9268a8335' 
  AND token = '1yR3+dCoviFU2nuG3fY0lYcRivhngKmbdYI2NgJ3/bg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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