SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f939146db825e127459f890bdeaa0c5c30489864037569fb5fe4e1a108b44dc2' 
  AND token = 'EUpEY7KUcp4kNopR/TCPi7cLPfThaGKxQ2EqAT9FRCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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