SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48dc124237ad50584853a5a64aec3bdb8a2c93992aea6b8822b77b0352df1ed8' 
  AND token = '8rVGF40/0j6WHmp+0SPFvQJO9hiLxIAL4Wxjpen+nBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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