SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bec510902ec8079d31a412a7d06d0f07995cc2e6cced55dbd7ab76fdad870641' 
  AND token = 'M0+eUMjUxwcHJb6HR6IhcvvKrpiMqeGlBUcgVHIIW2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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