SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3a3976836b920415698c0100fdcd02c0c70070a00337c3cebcb66eec5195271' 
  AND token = 'xyfTUIZf/2n/ELXS5hZrmw096hOhq50yvlCo8lDh2iI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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