SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c121b1dbe7604ae2c0344ef809a670a62bd47159eececcdd116be8f83fd1d948' 
  AND token = 'Ds4rJtJ8XpZgX09yMhNb9/V/eohyUFrYuGa65mBo7GQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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