SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12335f6b86d3f4444698ae378b75bb1e20f5f323cb6336bd1542fe76b9700ca3' 
  AND token = 'jdhRTi09jrWlh7+Rm1JU8zhywK0FFOh5RnZV/kcOQpE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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