SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ea64a232f9e1fab23b089e5c661686fc7768ec91086dd31dfb314b2107468b4' 
  AND token = '8C94VWiRbj024Sf6YTjkqIzYCW9pPm4PJl/gU/KRuUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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