SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e17a5bd99ae31b6ab1bb198f6d86f0bec18709e5b18a153525afd77a6c07be2' 
  AND token = 'Up3/CzdPMUx9+LiDLFY3Yc17+jDPkJWH9zzyu41I3Q8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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