SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35d6440811852cf78d430af4d6a7abdb8473a90b27e2a4daf74cbb6b82cf62f1' 
  AND token = 'vB3G4vJLAygGXHrqAluWNFoaGvhyAAKWsbizeCYlSWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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