SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4bf4326ab628d1e8a95f5614da6e96e53dd163845279bbcab2ba2480eb6cc55' 
  AND token = 'F6QpCNKB+QO87XFXtwx5sehtKlCb1fOTP1MOy2SHdbA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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