SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a052ba8c6ce39966e0fb980392d5123c8bf78a808ade719be53acb43ee83dc96' 
  AND token = '+yt2CUBzzcnmhryBn25opuJWaCNoII7514ewFGTDiWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}