SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99f220be8e1e7c0e33f02912451c04e5ced6b84ed38f26cbc6f464dd961a1d76' 
  AND token = '7JVlNTFsjiU9HwG21zxOcZxjWahXJwOBl1fnpYKDga8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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