SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf5363d5e2bd939ff16d61a28b2297de1dc6345a37948dbc8265c0fb98562826' 
  AND token = 'DWW1CxQDB82GvVRNKbHxmjAsubBanj6BdLNZ+b/HuFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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