SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37cc3b4211dce3d5e1261f3ad2c8336940d756122621eaae103c9326457b9709' 
  AND token = 'yFAsrgmCmLaPDeWHtZUfCABDqlwRk7CFnpMQ7WgcBa4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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