SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '639c016600ee6b3c02a0a78a30c9e34b982fd57494cd9c0fe9edfb21fd156e51' 
  AND token = 'OKlgu1YvPYM+47CGV9IrN/O3lsGW9qoLXA5P0EYlzuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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