SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4be8d633d5085d372e662cda1218ededf202b0e3a221b238ed780de1e53e1051' 
  AND token = '21HlFJ3jyPHBlz6NSaDYqMO2/7vitzf+oWW+FBmAwGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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