SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5d0bfa6041975899882f64c7dfab87e8d8676fea84390c12580ed69202fedc2' 
  AND token = 'zR2bmuL7M6kQt4rDHe8iaZ6SxAXcc68AJxCoFNC771U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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