SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ceb51d1cadd155468eae45f8ad70eacd639875a01136ada3cd7c8e2b9e556e80' 
  AND token = 't+qHhF0k5OsMYeFMxWW9B2RqEz7JBQSKkyRNQeboZyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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