SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0e94f45b1b4779c70d0c9cbf486b03d6fa720fe4b3aa788aad343a7ec354dc6' 
  AND token = '8r0O4+vQrwzeBz6TCvbLCgGKVZirccsHFJxtG8vlbh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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