SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7f980047c8c4d99ea0be4a91ac3a913c5d93d8722b942bbf6f6d0a2b7f2491f' 
  AND token = 'OaWBuAvJvi3ziTRgGBz3Bfi8SsZW+0jBN8Y08FHEkhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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