SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c4ae5c4d0178c01d3ebf9cffa8531ae9b7d8c1f72769ced0c69cede2f2146be' 
  AND token = 'r0Q1PBh+MtSvM4Znh1onHyrSEa03YC4nvtjIwe/wMBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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