SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3a7f9ab79a5ea876a00e85cee21450395fa475c91326df88926c9354e1a0269' 
  AND token = 'dGHMLZjjSvBfPXKYol9k/5sGPj+55ATicIrwd2ZO4Rk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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