SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '29ad2aa094809f790873e07e193bd7f1cdfab8d671bebb8adbbf5690f63173bc' 
  AND token = 'b9ugH+Eq4qsegYQ6FKS6Mxs3vPxGGLRbXk7WU+tYIVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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