SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f7539a99c1fee35c19a524779ee1e784c9d641c62b66a9130aed0536d1d8158' 
  AND token = 'y+9LUe4mWb8+Lx3KX6TYEKB2nUjVjCGJcuXqay6qNgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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