SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4b7e8682e6cbbfddeb409cb618cbe71527094d788d7d296de17d271c04ac09b' 
  AND token = '+2Qf/lupJqsv5RUBOjR8DgrZe6IQCQkblMAUclo4yaE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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