SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31221ea2a32477cd0d690dfd5492fa4f185a79888daeba41de83e288299aadf9' 
  AND token = 'z62TcQngDi7diDttbhO5EOEBwOB6Tkg/pnSyQzI81jg=' 
  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"
    }
  }
}