SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a2666e49072a2423ba596f0dfa1a2edbec7f1a76aef46ab0ad2143084bd38f9' 
  AND token = 'PIQPkr1t4zt6lpPLrb3TA+3h4xPvzkwmprgAVJsBLKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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