SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6890d0f7068ac9530d2212c420c124240817a8da180fff0b4804d28c0458e506' 
  AND token = '7hkCH165jNvfu9999ckLh/h5INKwundlc1hYxPisKMA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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