SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29df2ca7330de57db4908cdfe2285790559d64324c0f06c6e5f670af9ca1abb2' 
  AND token = 'rIePSY27VTjzJ+qVbNvz/epeCPNulIqGNKPmLISBg3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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