SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '866770bae912ccfe570b7f3b6280fdf8ceda54fc95f25956ca165fa42de6e50e' 
  AND token = 'F9Ho6mIO7jLVqd+Myfik3GDW2V93mLhSEZc7z4uxRN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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