SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '918b6ded372a808d04974149d829e86928a9ee6c3d1547def17580d8f0f0b203' 
  AND token = 'WiaT/J0dLDc4a7pqZjE2YRq/Do6SoVOoXa3iZTYk2r4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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