SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f17a0d8ae78d2242e8b67787ad7582babe183444b868509d98ca6af727980249' 
  AND token = 'GFfIzSXDrzQCNhIyfozR/Rf89lVMdqvNYvKcNeRut6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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