SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d76848185904e7363f415e71efbefc583722d58bc67fd381eee5cb0519f89fc' 
  AND token = '/AZFgjfvk80TjZoTfIEAM/3F0lWubbG3oCQ5xgu3ABQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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