SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c2f5fe93df82a109b37b807d3cb47a2320243e65558c7715067f5788c507df3' 
  AND token = 'jNRjs2aJlXs9hlAKDhMckHzk5TjjACZzOdwA2yIkCXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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