SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '138e3d95a90ff23e15e2e33c4f3764efca1511798d0310ed2dbbd0b399f0683b' 
  AND token = 'hxz14PNLN1V+QIFSxMtRybx/NokayDsbOGm4RfSztxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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