SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53b482f5d49afdcfbb230527861d573b1ec6995cfa0a409061d7cf1ff57164e4' 
  AND token = 'cB+hCOrgTOYqDNFMh5nvBiCScL2+ZD0uDtAUgfqHVJU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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