SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6778bad4a7c3b24189894b6a5408f6e2c5b760ff4f7f1d2d71d833161c9d8125' 
  AND token = 'Kx0lKpqvqN1yGcpotVYHwPykZUYnfXbTya2GRVt2HEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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