SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '572f58dd92d98505e8f063f827755513fc5f2be88eb56aa3ac1f4eac76a4abac' 
  AND token = 'AKiijY6yFAi8BhkI0Xmo6KofFSBuiVbCcNx2lYPyQQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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