SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd5b46cfae003f288b66af2a21783c4421a229305ff3d1b57cf4d00ea2138082' 
  AND token = 'da5lk3mJ+GO8L7CzRiWZ8KlYhGojzEy5lcJkkvynLVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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