SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0dbcdc2b69b9fe88f61b2a038f5f0514633f97dcfec3efbeb77441f13e860625' 
  AND token = '8R8MJFqI5pyJKNgfKu+CfKPnz5rJoSjR7LONEuhd5ss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}