SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0858825a6bccf8a1b42958b332daf44d9e3e32289abb3a9684f59a771e0f963' 
  AND token = 'LjWy07gRQFcrA+/Yh+pV1la5nvMfPVgw1hCPvJoASmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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