SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3137e0614d26bc9b2aed12d7c914a3fbe2955d2a3ebcdade50e95e30105b3202' 
  AND token = 'CMgOp4UZ+MagOgwxrlij90rt6F/0++BqVsFDK10w89E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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