SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2d0833a6d27e068897e34fc630947c17dccc477dd2267e2a6f94be4bb0d9535' 
  AND token = 'S+U+q/q/pGRZURILXl4eJTko53wp/fBew/SzJNcr4Mg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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