SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1abea06f3f204836b49feb0361bad000a6e20199dc8b1bf130ed98a2c920651' 
  AND token = 'N51VJEQdO2h4BCx4mrMyhWmVVhz/c2tfMl83yOjEGu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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