SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe125f8d7f31a7da39e56567c7450c8dd882203f2ddd15549f271c109350391d' 
  AND token = 'qSQQudmpd1GeiegV35uxMuLtuVV9sbtaqnpUTV/hYEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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