SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fff5ae64813a4735de17aa88969537cc760878e52c8bf2dfa1ca646b8bfaeb20' 
  AND token = 'z1qD8M/5NjdO7yKLwHcJYZJyitfoxKlsWbK+h9LbGdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}