SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37e0ce0f676c230d9924e978820e3b2318d5a250ded51b4c1d304584ff215124' 
  AND token = 'sRwzIfciPobTLvNqhtT3dbJIUOaAxgBB/QZZ8cKPgRI=' 
  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"
    }
  }
}