SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b893b47359b81e679d721b184185fda32eca40eb06e27ae89f8f53b0a5cb9d12' 
  AND token = 'EUEENTA2RFagnAUmsp11otSK4nACUDV2XUmBnY5tPzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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