SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51ba7793dffad87794d601760ae1d7a6344aaae432597305b21218e298135252' 
  AND token = 'VWZn+mrDtWYPY8QHk6Q2r+m78jnCiT7bsvuuOA9qd6I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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