SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df83db29c41c6116cbdd6b09c140e1a0b4ed9235e47bb17f982305b22a0c9ea3' 
  AND token = 'MKxqbopYuEgFuvpaYs7UlOdeKV8akV5KO37xUnfLEHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}