SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ebbe0a539c58b603b980a8eee3ddc72792805711ca5db0aa9241a9bf424de50' 
  AND token = 'YN4QXYr54U/GKGN3To/OcbaHrqL5fdq9aNVEGFLLUCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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