SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d4b95d41891e4a3c1501ee6c268aa511b22fffd75dfcb9ca6402d6f8ca339b7' 
  AND token = 'MxBND+ceoUYmFEbeSXuRA9oBXnMFYzF18mhYLhn+Q/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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